Re: [dtn-interest] Bundle Protocol question

[<[e-mail]>]

Kurtis,

Not surprised you're having problems with the length 'field' - it's an SDNV.
That's described briefly in section 4.1 of RFC5050. Note the (*) in the diagram
in section 4.5 of RFC5050.

It was recognised that more documentation of SDNVs was needed for implementers,
so the workgroup draft:
http://ietfreport.isoc.org/idref/draft-irtf-dtnrg-sdnv/
was adopted after:
http://tools.ietf.org/html/draft-eddy-dtn-sdnv-03
was written. But that workgroup draft has been allowed to expire, with no further
interest expressed in it from the chairs.

(I'd have aimed to have the SDNV draft published as an RFC before or with RFC5050,
as the dependency is obvious.)

hope this helps,

L.

<http://www.ee.surrey.ac.uk/Personal/L.Wood/><[e-mail]>



-----Original Message-----
From: [e-mail] on behalf of Kurtis Heimerl
Sent: Mon 2008-11-17 7:29
To: [e-mail]
Subject: [dtn-interest] Bundle Protocol question
 
Hello again DTN-interest! I've made great strides on the python DTN
implementation, and can send and receive smaller bundles over the
TCPCL.

I've begun work on allowing for larger files. For small files, the
implementation was allowed to strip off the type, flags and length
fields from the Bundle Payload block and assume the rest is payload.
However, as the payload gets larger, this fails.

I need a field that indicates the length of the payload, but it turns
out that the block length field of the Bundle payload block isn't
anything obviously correct. It seems to return 8 if the bundle is
small and 4096 if large. It doesn't depend on the length of the
payload, that much I'm certain about. This means either I'm
incorrectly decoding this variable, which I find unlikely due to the
correctness of the rest of the fields, or it's not what I thought it
was. Where am I supposed to get this length?

Also, are any of the DTN implementations more readable than the
reference of symbian implementations? It's hard to parse those, so a
simpler version might lead me to unblocking myself more often.

Thanks!